With the increasing involvement of volunteers in caring for persons living with AIDS (PWAs), it becomes critically important to understand the social and psychological aspects of this type of volunteerism. Guided by a conceptualization of volunteerism as sustained, ongoing helping behavior, relevant psychological theories are being applied in this program of research on AIDS volunteerism to understand three major stages of the volunteer process. The first stage concerns the antecedents of AIDS volunteerism, and addresses the questions of who volunteers and why. The second stage examines the experiences of volunteers and focuses on features of the helping relationships that develop between volunteers and the beneficiaries of volunteerism. The third stage focuses on the consequences of AIDS volunteerism for the volunteers themselves, for members of their social networks, and for society at large, including examining the roles AIDS volunteers can play in AIDS prevention and in influencing public knowledge about and perceptions of AIDS. The proposed research involves converging cross-sectional and longitudinal field investigations of currently active AIDS volunteers working with community-based AIDS volunteer organizations. This program of research has the potential not only to increase understanding of sustained helping behavior but also to contribute to the optimal utilization of volunteers in three major aspects of society's response to AIDS: caring for PWAS, AIDS prevention, and public education.